A Very Stable Genius: Donald J. Trump's Testing of America by Philip Rucker and Carol Leonnig:
Kushner was the classic profile of a person who would be rejected for national security clearance, and Kelly’s move to downgrade his clearance level provided comfort to the CIA. Agency officials had been wary of allowing Kushner to see highly sensitive information about sources and methods, based on his pattern of talking to foreign leaders in the Middle East—including Mohammed bin Salman, Saudi Arabia’s crown prince—without State Department diplomats or other government experts guiding him.
The intelligence agencies were on guard in part because, as the Post reported on February 27, they had intercepted private conversations of leaders in China, Israel, Mexico, and the United Arab Emirates talking about the ease with which they could manipulate Kushner. Some of these foreign leaders described Kushner as naïve and easily pushed; others said his financial debts and search for refinancing for an underwater Manhattan skyscraper were one route that made him vulnerable to pressure.